Why website speed matters (and how to measure it)
A slow website drives visitors away and hurts your search rankings. How to measure your website’s speed and what to do to improve it.
Published on · Performance, SEO
A visitor staring at a blank page for several seconds is likely to leave, especially on mobile. Website speed is not a technical detail: it directly affects the number of inquiries and sales you get, as well as your position on Google.
What Google measures
Google evaluates the visitor experience through three metrics called Core Web Vitals:
- LCP (Largest Contentful Paint): how long it takes for the main element of the page to appear. It should stay under 2.5 seconds.
- INP (Interaction to Next Paint): how quickly the page responds when you click or type. It should stay under 200 milliseconds.
- CLS (Cumulative Layout Shift): how stable the layout is while loading. Elements should not “jump” around.
How to measure your website’s speed
The free tool PageSpeed Insights analyzes any page in a few seconds. It gives a score out of 100 for mobile and desktop, along with real-world data from your visitors when available.
Start with your homepage and your most visited pages, on mobile: it is the most demanding version, and the most used.
The most common causes of slowness
- Oversized images, served at their original size instead of being compressed and resized for the screen.
- Too many scripts and plugins, especially on websites built with generic themes.
- Unsuitable hosting, located far from your visitors or shared with a large number of websites.
- Fonts and videos loaded unnecessarily on every page.
What really makes a difference
The biggest gains often come from how the website is built in the first place: generating lightweight pages, loading only what is needed, and serving files from a network close to your visitors. That is why performance should be designed in from the start, rather than fixed after the fact.